Any smog gurus willing to chime in?

[Marlon671]

I purchased an 86 325e a few weeks ago. Had it sit in the garage to wait for parts to trickle in. PO did the stroker conversion (325i head).

Yesterday I go in for smog and failed due to high nox numbers. I'll post my results if anyone can take a closer look and suggest anything I can check and/or replace before I dive in and change out the cat as the smog shop owner suggested. Also was suggested to replace o2 sensor and cap and rotor assembly. So far, plugs were replaced right before smog. And I did drive about 30 mins prior to smog and let the car idle before smog.

Any advice would be appreciated. Thanks!

[mr.vang]

Which DME are you running?

[Marlon671]

Im not sure which it is exactly but i do know he installed a different dme because the PO had the 325e dme in the trunk when I purchased it. I can double check when i get home.

[Preyupy]

The CO% shows it is very lean, that can bring the NO and HC up (I'm seeing a high HC at 15mph) There is a good chance that the Cat Converter is shot also.

[Marlon671]

Yea smog tech highly suggest replacing cat... Any recommendations as an alternative to getting butt raped by BMW?

[RCtheRed]

Hate to say it but you will probably need a new cat. What you could do is replace O2 sensor and air filter, and take it for a long drive and get your current Cat warmed up and really hot. Also you could run some pass smog fuel if you really wanna try anyway resort before replacing the cat. Maybe even try sea foam and an oil change.

[reelizmpro]

90 to 10 on HC is a pretty big difference. Other than that, I'd say you need a new cat as well. It'll drop the NOx number down significantly.

[wilholl]

Yea smog tech highly suggest replacing cat... Any recommendations as an alternative to getting butt raped by BMW?

No need to buy an OEM cat from the dealer. Shop around for a shop that will install a California legal aftermarket cat.

[Marlon671]

Thanks for replies. Current game plan is new cap and rotor, oil change, fix a minor exhaust manifold leak, search for vacuum leaks, new o2 sensor, new fuel filter and while I'm at it I might as well check valve clearances. I figure those are parts are subject to wear and tear and it's probably good to time to replace em since PO didn't maintain the car too well. If all else fails, I'll replace the cat.

[itsonlygeorge]

When was the timing belt and waterpump last done?


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[Marlon671]

When was the timing belt and waterpump last done?


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U know what, I'm actually not certain. If I remember correctly, the water pump and timing belt were changed during the head swap.

[diggity_1031]

Looks to be too lean. Check your fuel pressure, vacuum leak, o2 sensor etc...........

[Marlon671]

will do! thanks!

[kickinindian]

i used some pure ethanol mixed into one gallon of 87 for my subaru to pass. was way under, when i bought it from the guy he tried to smog it a month earlier and if didnt pass i said fuck it and tried it out and it worked pretty good!

[Marlon671]

i used some pure ethanol mixed into one gallon of 87 for my subaru to pass. was way under, when i bought it from the guy he tried to smog it a month earlier and if didnt pass i said fuck it and tried it out and it worked pretty good!

That's pretty interesting. Gotta look into that...